This invention relates generally to a refrigerant recovery and purification system capable of withdrawing refrigerant from a disabled or inoperative refrigeration unit, removing impurities from the refrigerant, cleaning and reconditioning the refrigerant and returning it to the refrigeration unit after repair. The invention relates more specifically to such a system where the inherent cooling potential of the refrigerant is utilized to accomplish one stage of the purification process. The invention further relates to the method of accomplishing the removal and purification where the inherent cooling potential of the refrigerant itself is utilized to purify and cool the refrigerant for storage or replacement into the refrigeration unit.
During the continued operation of a refrigeration system, the refrigerant becomes contaminated with impurities such as moisture, acids and particulate matter. When the system needs repair, the standard practice is to simply bleed the system to atmosphere. This method, however, wastes refrigerant, since it can be cleaned and reused, plus it is now known to be a major source of pollution. The CFC's contained in the refrigerant have been shown to cause major damage to the ozone layer.
Prior art has taught recovery systems which remove the contaminated refrigerant for purification, and it is now known to have systems which both remove and purify the refrigerant. Such systems are then capable of returning the clean refrigerant to the repaired refrigeration system. For example, U.S. Pat. No. 4,476,688 to this inventor teaches such a system. That patent teaches a system comprising a compressor, purification units, a condenser and storage tanks. .Another such system is taught in U.S. Pat. No. 4,646,527 to Taylor. This system also utilizes a compressor, purification units, a condenser and storage tanks.
A major short-coming of the prior systems is that a prime source of thermodynamic energy, that of the refrigerant being removed, is not put to any use and is therefore completely wasted. A second disadvantage is that the systems require a condenser unit to sufficiently cool the refrigerant after purification for storage and replacement in the refrigeration system. This condenser requires outside fans and energy sources to accomplish the cooling task.
It is an object of this invention to provide a method and a refrigerant recovery and purification system, capable of removing and purifying contaminated refrigerant from a refrigeration system and then storing and/or returning this clean refrigerant to the same refrigeration system, where the refrigerant being removed is utilized as a source of energy for a purification step.
It is a further object of this invention to provide such a method and system where the refrigerant is sufficiently cooled by the purification process such that a condenser is not required to be a part of said system.
It is a further object of this invention to provide such a method and system where the refrigerant being removed is allowed to expand and pass through coils contained within a dehydrator-purifier, thereby cooling or freezing the coils. The refrigerant is then forced through the coils and impurities are condensed onto the coils while the clean refrigerant evaporates and continues through the system.